Energy level gamut-a wide-angle lens to look at photoelectronic properties of diketopyrrolopyrrole-benzothiadiazole-based small molecules.

Demands in the field of molecular design for optimized bandgap and proper energy levels to obtain high efficiencies are growing progressively in organic electronics. In the present work, we designed a series of molecules based on diketopyrrolopyrrole (DPP) and benzothiadiazoles (BT). We also studied the efeect of the presence and position of the nitrogen atom as an effective heteroatom. Finally, we optimized the energy levels of the designed structures to find the most favorable donor properties along with fullerene and non-fullerene (NF) acceptors in bulk heterojunction (BHJ) solar cell systems. To shed new light on the electronic characteristics of the designed structures, we developed a correction gamut of the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy levels. The gamut is a span that predicts the occurrence of practical HOMO or LUMO with high probability from density functional theory computations in the gas phase. The model was validated using experimental energy level values of a similar structure as reference material. The results obtained by the new pathway of combining the idea of energy level gamuts with the modified Scharber model for NF BHJ suggested that the designed structures can afford power conversion efficiencies (PCE) for NF-BHJ of 8.5-10.5%. Graphical abstract Improved approach for predicting power conversion efficiencies (PCE) of designed molecules.

Hybrid Benzoxazole-Coumarin Compounds Induce Death Receptor-Mediated Switchable Apoptotic and Necroptotic Cell Death on HN-5 Head and Neck Cancer Cell Line.

BACKGROUND: Efficacy of multimodality approaches for the treatment of squamous cell cancer of the head and neck has remained unsatisfactory and further advances are critically required. Targeted cell death induction is a novel therapeutic approach that may help to improve clinical management of Head and Neck cancer patients. OBJECTIVE: The potency of novel hybrid benzoxazole-coumarins on the induction of apoptotic and/or necroptotic cell death were evaluated in a Head and Neck carcinoma cell line, HN-5, and a human skin cell line, AGO1522. METHODS: Quantitative toxicity of the synthesized compounds were elucidated by MTT assay, the specific activity of caspase-3 and -9 were measured by the colorimetric method and zVAD was used to block apoptosis. Expression of cell death related genes were studied using quantitative PCR. RESULTS: All three compounds were revealed IC50 value around 51.96±7.15 microM in HN-5 cells which were significantly lower than observed IC50 for AGO1522, 121.93±3.66 microM (p=0.001). Significant increase expression of FAS, FASL and TRIAL were observed in the treated cells with or without pretreatment with zVAD. In the absence of pretreatment, treatment lead to the induction of apoptosis with a significant increase in caspase-3 gene expression and caspase-3 activity without a significant increase in expression or activity of caspase-9 and other components of the intrinsic apoptotic pathway. However, in the zVAD pretreated cells, necroptotic cell death with a significant increase in expression of RIP1, RIP3, and MLKL genes was observed Conclusion: The novel hybrid benzoxazole-coumarins effectively induce Caspase-3 dependent apoptosis in HN-5 cancer cells, but also could circumvent the blockage of apoptotic cell death by induction of necroptosis.

Development of molecular photoswitch with very fast photoresponse based on asymmetrical bis-azospiropyran.

To study the effects of an extended bis-azo conjugated bridge with two different photochemical functions on a molecule in photochromic responses, a novel asymmetrical bifunctional bis-azo spiropyran photochromic dye was designed and synthesized. The obtained photoresponses were compared with symmetrical bifunctional bis-azo spiropyran analogues, and relative mono-azo and simple spiropyrans. Colourimetric behaviour, luminescence, and switching kinetics of all the dyes were studied. The largest molar absorption coefficient in merocyanine form, quickest response to light, and highest fluorescence quantum yield of the spiropyran form with a superior ratio of emission intensities of spiropyran to merocyanine form were achieved for the asymmetric bis-azospiropyran. Solvatochromic effect was studied to observe the solvent effects on non-irradiation colouration of the photochromic dyes. Furthermore, The molecular energy levels for optimized geometries of the synthesized bis-azospiropyrans and their probable photochemical products were obtained at the B3LYP/6-31G(d) level of theory.

A 'chemically-gated' photoresponsive compound as a visible detector for organophosphorus nerve agents.

We describe a versatile and convenient visible detection method for organophosphorus compounds based on a colorless 'pro-photoresponsive' organic molecule that undergoes photochemical ring-closing to produce a colored isomer only after it reacts with vapors of the phosphorylating agent.

Development of cloud point extraction for simultaneous extraction and determination of gold and palladium using ICP-OES.

Cloud point method was applied for the simultaneous extraction and preconcentration of trace amounts of gold and palladium. The extraction of analytes was performed in the presence of 1,8-diamino-4,5-dihydroxy anthraquinone as chelating agent and Triton X-114 as a non-ionic surfactant. After phase separation, the surfactant-rich phase was diluted with concentrated HNO(3) (65%, w/w) and the analytes concentrations were determined by inductively coupled plasma-optical emission spectrometry (ICP-OES). The variables affecting the complexation and extraction conditions were optimized and under the optimum conditions (i.e. pH 6.5, 2.2 x 10(-4) mol l(-1) chelating agent, 0.15% (w/v) of Triton X-114, equilibration temperature 55 degrees C, centrifuge at 3500 rpm), quantitative extraction of Au(III) and Pd(II) from 100 ml of the aqueous solution was performed. The calibration curves were linear in the range of 0.5-1000 microg l(-1) with detection limits of 0.5 and 0.3 microg l(-1) and the enrichment factors were 8.6 and 20.2 for Au and Pd, respectively. Also the precision (%RSD) for eight replicate determinations of the analytes was better than 5%. Finally, the proposed method was successfully applied for the determination of Au and Pd in mine stones and standard reference materials (SRM).